410 
POPULAR SCIENCE REVIEW. 
Britain and Ireland, is twenty, of which four occurred in 
Scotland, and four in Ireland. The largest and most notice- 
able of all these fell on December 13, 1795, near Wold Cottage, 
in the parish of Thwing, East Biding of Yorkshire. Its 
descent was witnessed by two persons ; and when the stone 
was dug up, it was found to have penetrated through no less 
than 1 8 inches of soil and hard chalk. It originally weighed 
about 56 lb., but that portion of it preserved in the British 
Museum is stated in the official catalogue toweigh 47 lb. 
9 oz. 53 grains — -just double the weight of the Devonshire 
aerolite. 
When we come to inquire into the various opinions which 
have been held in different ages respecting the origin of aero- 
lites, and the power which causes their descent, we must go 
back to the times of the ancient Greeks, and we find that 
those of their philosophers who had directed their attention to 
the subject had four theories to account for this singular 
phenomenon. Some thought that meteoric stones had a 
telluric origin, and resulted from exhalations ascending 
from the earth becoming condensed to such a degree as to 
render them solid. This theory was in after-years revived by 
Helper, the astronomer, who excluded fire-balls and shooting 
stars from the domain of astronomy ; because, according to 
his views, they were simply “ meteors arising from the exha- 
lations of the earth, and blending with the higher ether.” 
Others, like Aristotle, considered that they were masses of 
metal raised either by hurricanes, or projected by some vol- 
cano beyond the limits of the eartlfis attraction, so becoming 
inflamed and converted, for a time, into star - like bodies. 
Thirdly, a solar origin ; this, however, was freely derided by 
Pliny, and several others, amongst whom we may mention 
Diogenes of Apollonia, already alluded to as one of the 
chroniclers of the aerolite of HDgos Potamos. He thus 
argues : “ Stars that are invisible, and consequently have 
no name, move in space together with those that are visible. 
.... These invisible stars frequently fall to the earth and 
are extinguished, as the stony star which fell burning at Hjgos 
Potamos.” This last opinion, it will be seen, coincides, as far 
as it goes, almost exactly with the most modern views on the 
subject. 
As some of the Greeks derived the origin of meteorites 
from the sun (probably from the fact of their sometimes falling 
during bright sunshine), so we find, at the end of the seven- 
teenth century, it was believed by a great many that they fell 
from the moon. This conjecture appears to have been first 
hazarded by an Italian philosopher, named Paolo Maria Ter- 
zago, whose attention was specially directed to this subject on 
